Abstract: A method and an apparatus for determining a variable describing the speed of a vehicle are provided. In this method, for at least two wheels, the speeds of those wheels are determined, and the variable describing the speed of the vehicle is determined at least as a function of the speed of a selected wheel. For this, an operating state of the vehicle is determined based on the speeds of at the least two wheels, the selected wheel being determined at least as a function of that operating state. In addition, plausibility queries for determining the selected wheel are performed for some of the determined operating states of the vehicle, as a function of the particular operating state of the vehicle that is determined.

Abstract: A method and system for the determining in advance of the travel corridor of a motor vehicle for an automatic system for establishing a safe tailing distance in which a signal corresponding to the speed is used to determine a turning radius of the motor vehicle, the travel corridor being determined from the turning radius.For the exact determination of the travel corridor of the motor vehicle, and in order sufficiently to take into consideration the travel dynamics of the motor vehicle, the speed of at least two wheels of the vehicle are measured and the yawing of the vehicle determined from the difference between the two wheel speeds.

Abstract: The present invention provides a tire air pressure reduction detecting apparatus arranged such that both an ABS processing and an air pressure reduction judgment processing can be executed with a single microcomputer. A vacant period of time t.sub.n for timing waiting is prepared in each ABS cycle. Utilizing such vacant periods of time t.sub.n, an air pressure reduction Judgment processing is dispersively executed in a time-division manner in a plurality of such vacant periods of time t.sub.n (FIG. 4).

Abstract: For cornering identification in an anti-lock control system and/or traction slip control system, wherein the rotational behavior of the wheels is measured and evaluated to determine a vehicle reference speed, and wherein criteria for cornering identification are derived from the wheel slip, the slip signals of the individual wheels are filtered and the signals sent are compared. Cornering is identified when simultaneously the filtered wheel slip on both front wheels is in excess of a predetermined maximum value and the filtered wheel slip values of one rear wheel exceed and that of the other rear wheel fall below a predetermined value. The threshold values depend on the vehicle reference speed. The direction of cornering is also identified.

Abstract: A method of monitoring the relative effective diameters of the tires and compensating therefor in a vehicle which includes a front driveshaft for transferring motive power to a front set of wheels and a rear driveshaft for transferring motive power to a rear set of wheels, each of the wheels having an effective diameter. Front and rear driveshaft values indicative of the rotational speed of each driveshaft are generated. A difference value indicative of a difference between said front and rear driveshaft values is then generated. A low pass filtered value is generated according to the relationship of Y.sub.1p =(1-.beta.)*U(k)+.beta.*Y.sub.1p (k-1). The low pass filtered value is monitored for a predetermined period of time to determine if one of the wheels has a smaller effective diameter than the other wheels.

Abstract: A method of monitoring a brake system which is equipped with anti-lock control (ABS) and a system for electronic control of brake force distribution (EBV). The system includes two brake circuits in a black/white brake circuit split-up, the EBV function or control is principally released only when the vehicle deceleration exceeds a predetermined limit value (GWN). To identify a front-axle brake circuit failure, acceleration criteria, i.e., criteria responsive to the acceleration behavior of the vehicle wheels, are predetermined and monitored. Further, slip range monitoring in conjunction with acceleration range monitoring is performed.

Abstract: The pressure increases of a hydraulic pressure control module for controlling the braking forces of wheels are decided on the basis of wheel speeds and a vehicle speed estimated from the maximum wheel speed. In this case, on condition that the incremental rate of the vehicle speed exceeds a predetermined threshold value, the vehicle speed exhibited before the incremental rate exceeds the threshold value is kept as an estimated vehicle speed, which is used for deciding the pressure increases. Thus, the pressure increases can be appropriately decided even in a situation where a motor vehicle passes through a very-low-.mu. road part or a drop in road level.

Abstract: A vehicle yawing behavior control apparatus for controlling the vehicle behavior to bring the actual vehicle yawing motion into agreement with the calculated target value calculated based on the parameters representing a condition of vehicle movement. At least vehicle yaw rate and slip angle representing an actual value of vehicle yawing motion is detected. When the detected vehicle slip angle is directed outside with respect to the vehicle movement and is greater than a reference slip angle, the calculated target vehicle yawing motion value is corrected outside with respect to the vehicle movement to a greater degree at a greater deviation of the detected vehicle slip angle from the reference slip angle. The reference slip angle is increased as the calculated target vehicle yawing motion value increases.

Abstract: A method of controlling the amount of power delivered to the front driveshaft and to the rear driveshaft of a motor vehicle including the steps of generating a front driveshaft value indicative of the rotational speed of said front driveshaft and generating a rear driveshaft value indicative of the rotational speed of said rear driveshaft. A vehicle speed is generated based on the lower of said front driveshaft value and said rear driveshaft value. The amount of power delivered to said front driveshaft and to said rear driveshaft is controlled as a function of said vehicle speed.

Abstract: An active brake control method including an improved method of developing the desired state variables, enabling the system designer to specify the damping ratio and the un-damped natural frequency of desired vehicle performance. The desired state variables are determined by converting a linear time domain model into a transfer function model and solving for the lateral velocity and yaw rate as a function of the driver steering angle, the damping ratio, the un-damped natural frequency of the vehicle, and the transfer function zeros. The damping ratio, the un-damped natural frequency of the vehicle, and the transfer function zeros may either be computed or specified in a look-up table as a function of vehicle speed. This allows the system designer to provide increased damping at high vehicle speeds, for example.

Abstract: A device for estimating slip angle of vehicle body of a vehicle, having: means for calculating yaw rate based upon such parameters as detected steering angle, vehicle speed, lateral acceleration and braking forces as variable parameters, the slip angle of the vehicle body estimated by the vehicle body slip angle estimation device, a first feedback factor multiplied to difference between the detected yaw rate and the yaw rate calculated by the yaw rate calculation means, and fixed parameters particular to the vehicle, such that the calculated yaw rate converges to the detected yaw rate; means for calculating slip angle of the vehicle body based upon such parameters as detected steering angle, vehicle speed, lateral acceleration, braking forces and yaw rate, the yaw rate calculated by the yaw rate calculation means, a second feedback factor multiplied to the difference between the detected yaw rate and the yaw rate calculated by the yaw rate calculation means, and fixed parameters particular to the vehicle, suc

Abstract: A method is provided to correct the wheel speed for a vehicle equipped with a mini tire as the spare tire plus a nonvolatile memory device. The presence or absence of a mounted mini tire is detected while the vehicle is moving, and if a mini tire is mounted, the mounting information is stored in the nonvolatile memory. If an antilock control is triggered after the vehicle is restarted and in motion, a correction is made for the mini tire using the mounting information stored in the nonvolatile memory.

Abstract: A gear shift control device of an automatic transmission of a vehicle, including: a means for estimating a target shift stage for harmonizing rotation speed and power output of engine of the vehicle; a means for estimating slip angle of at least one of the pair of drive wheels; a means for estimating slip ratio of the at least one drive wheel which would be caused thereon by the automatic transmission being shifted to the target shift stage; a means for estimating tire grip of the at least one drive wheel based upon the estimated slip angle and the estimated slip ratio; a means for judging if the estimated tire grip of the at least one drive wheel is in a grip range predetermined therefor; and a means for executing gear shift of the automatic transmission when the target shift stage is different from a current shift stage with the estimated tire grip being within the predetermined grip range.

Abstract: The present invention is directed to a vehicle motion control system for maintaining vehicle stability by controlling the braking force applied to each wheel of a vehicle. The braking force applied to each wheel is controlled on the basis of outputs of the wheel speed sensors and the vehicle speed estimation unit. A limit value is calculated to a difference between a first estimated vehicle speed calculated for a second wheel located on the right side of the vehicle and a left estimated vehicle speed calculated for a left wheel located on the left side of the vehicle. The calculation of one of the first and second estimated vehicle speeds is limited in response to the limit value, so as to keep the estimated vehicle speed calculated for one of the right and left wheels rotating at a relatively low speed to be greater than a value subtracting the limit value from the second estimated vehicle speed provided for the other one of the right and left wheels rotating at a relatively high speed.

Abstract: A circuit arrangement for conditioning and evaluating the signals emanating from wheel sensors in a first stage determines the sensor(s) supplying the highest useful signal at very low wheel speeds. The signal from the most sensitive sensor is delivered when the wheel speed is below the predetermined speed threshold. Above the speed threshold, however, the signal from a sensor arranged on a driven vehicle wheel is used as the vehicle speed signal. The circuit is especially suitable for anti-lock and traction slip control systems which supply speed signals which can also be evaluated for other vehicle control or regulating systems.

Abstract: A slip rate of the driven wheel is calculated (at step S1). When the slip rate is smaller and when the slip rate is larger (at steps S2 and S3), estimated road surface friction coefficients MUTG and MUFG are determined by searching a table, based on a total grip force TGS or a longitudinal grip force FG determined from a vehicle acceleration (at steps S4, S7, S5 and S9). The larger one of the estimated road surface friction coefficients MUTG and MUFG is selected as MUCON (at steps S10, S11 and S12). A minimum total grip force TGMIN determined by searching a table and based on MUCON is compared with the total grip force TGS determined from the vehicle acceleration (at step S13), and the larger one of the minimum total grip force TGMIN and total grip force TGS is delivered as a total grip force TG for traction control (at steps S14 and S15). Thus, it is possible to estimate a correct total grip force, taking the road surface friction coefficient into consideration.

Abstract: Detection means are provided which detect the rotational movements of the wheels, a variable which represents the steering angle, and at least one variable which represents the lateral movement and/or the yawing movement of the vehicle. Signals for influencing actuators for braking the wheels are formed by controller means as a function of the detected data in such a way that a control variable which is dependent on at least the detected lateral movement or yawing movement of the vehicle is adjusted to a desired range of control variables, that is to say the actuators are influenced in such a way that the control variable is kept within a desired range. This desired range is defined by two specific limit values.

Abstract: A four-wheel drive vehicle includes a transfer case for controlling the delivery of power between the front and rear wheels of the vehicle. A clutch in the transfer case controls the amount of power delivered to the front and rear wheels in response to a clutch PulseWidth Modulated (PWM) signal which is generated by an electronic powertrain controller. The powertrain controller receives a first signal which is indicative of the rotational speed of a front driveshaft, which transfers motive power from the transfer case to a pair of front wheels, and a second signal which is indicative of the rotational speed of a rear driveshaft, which transfers motive power from the transfer case to a pair of rear wheels.

Abstract: An active torque-split control system for a four-wheel-drive vehicle comprises a transfer clutch, and sensors for detecting a wheel-speed difference between a primary drive wheel and a secondary drive wheel, a throttle opening, a vehicle speed, depressed or undepressed states of a brake pedal. The system is capable of executing both a feedback control based on the wheel-speed difference and a feedforward control based on the throttle opening. The system is responsive to at least a feedback control signal from the feedback control system and an anticipating correction signal from the feedforward control system for determining a distribution ratio of driving torque of the secondary drive wheel to the primary drive wheel depending on the highest one of the feedback control signal value and the anticipating correction signal value.

Abstract: A method of an accurate detection of a spinning vehicle wheel. Observed wheel speeds are derived by measuring the speed of each wheel and the slowest speed is set as the slowest observed wheel speed. A maximum probable wheel speed is derived by multiplying the slowest observed wheel speed by the ratio of the maximum wheel speed to the slowest wheel speed for a given minimum turning radius. The maximum probable wheel speed is compared with an observed wheel speed and if the observed wheel speed is greater, the wheel is deemed to be spinning.

Abstract: A movement variable which represents the movement of a vehicle is controlled by actuating at least one actuator for applying a braking force to the wheels. Controller means use controller internal variables to form signals for influencing the actuators with the effect of adjusting a control variable. The controller means has a first area adapted to the respective selected sensor configuration in such a way that the controller-internal variables are formed on the basis of the sensor signals, and a second area for processing the controller-internal variables independently of the selection of the sensor configuration. As a result, simple adaptation with low development and application outlay to a wide variety of sensor configurations is possible.

Abstract: The hydroplaning-occurring speed of a vehicle is estimated by detecting an amount of water on a wet road surface on which the vehicle is traveling, and estimating a speed of the vehicle at and above which a hydroplaning phenomenon can occur, based on the detected amount of water. The possibility of occurrence of a hydroplaning phenomenon of a vehicle is detected by detecting an amount of water on a wet road surface on which the vehicle is traveling, detecting the speed of the vehicle, and determining whether there is a possibility that a hydroplaning phenomenon can occur, based on the detected amount of water and the detected speed of the vehicle.

Abstract: This invention of a proportional force modulation wheel slide protection process for steel wheel/steel rail vehicles. It applies particularly to self-propelled transit type railway vehicles. It uses a slide detection logic which predicts the force reduction needed to control slippage and correct the slide condition. The force modulation is made on the basis of the initial prediction and the time that a slide has been in effect to determine if greater force reduction is needed to effect a slide correction. Sensing of positive to negative axle rate polarity shift is used to determine when a slide has been corrected and normal braking force can be restored. This process is used to control slides by modulating both the dynamic and friction braking in like manner. The normal braking control devices are used to reduce braking force during slide correction. Although this process could be implemented through the use of discrete circuits, it lends itself to microprocessor applications.

Abstract: A vehicle speed detecting apparatus wherein the speeds of vehicle wheels are detected by wheel speed detecting devices, and the vehicle running speed is estimated by a vehicle speed estimating device, on the basis of the detected wheel speeds, and according to a predetermined estimation rule. The vehicle speed estimating device includes a noise detector for detecting a noise included in any one of the detected wheel speeds, and a rule changing device for changing the estimation rule depending upon whether the noise is included in the detected wheel speed or speeds.

Abstract: A method for improving the controllability of motor vehicles during braking wherein desired slip values are determined and adjusted with the aid of a wheel slip controller. According to the method, the following are measured: the yaw rate .psi., the steering angle .delta., the wheel speeds V.sub.Ri, the inlet pressure P.sub.inlet or wheel brake pressure P.sub.i, and, if required, the engine speed and the throttle valve angle. The following variables are estimated using the measured values: the longitudinal vehicle speed V.sub.X, the longitudinal vehicle acceleration V.sub.X, the wheel slip values .lambda..sub.i, the braking forces F.sub.Bi, the tire forces F.sub.Ri, and the transverse speed V.sub.Y. Desired slip values .lambda..sub.i * are then determined from these measured and estimated variables with the aid of a simple vehicle model and supplied to the slip controller to control the vehicle wheel brake pressure.